Resource depletion

Organic farming is based on ecological farming principles that seek to rely on 'closed' systems of fertility on the farm. Farmyard waste in the form of manure and compost is put back onto the land, while 'green manures' – plants that fix nitrogen in their roots – are used to build soil fertility. This agro-ecological approach to farming relies on taking good care of the soil itself, and is the opposite of more intensive approaches where yields rely on adding large amounts of fertiliser, and then pesticide, each year which leaves the eco-system out of balance. The problem with this intensive approach is that eventually those finite inputs will run out.

Peak phosphate

For example, our new report reveals that supplies of phosphate rock are running out faster than previously thought and that declining supplies and higher prices of phosphate are a new threat to global food security. ‘A rock and a hard place: Peak phosphorus and the threat to our food security’ highlights the urgent need for farming to become less reliant on phosphate rock-based fertiliser.

Worldwide 158 million tonnes of phosphate rock is mined every year, but the supply is finite. Recent analysis suggests that we may hit ‘peak’ phosphate as early as 2033, after which supplies will become increasingly scarce and more expensive.

This critical issue is missing from the global policy agenda. Without fertilisation from phosphorus it has been estimated that wheat yields could more then halve in coming decades, falling from nine tonnes a hectare to four tonnes.

We all – the public, farmers and politicians – need to take this issue seriously and start preparing now. Necessary actions include:

Changing how we farm: Organic farms are more resilient to the coming phosphorus rock ‘shock’, with a greater capacity to scavenge for nutrients through denser and deeper root systems.

Changing how we deal with human excreta: Globally only 10% of human waste is returned to agricultural soils. Urine alone contains more than 50% of the phosphorus excreted by humans.

Changing what we eat: Eating less meat can reduce the demand for mined phosphate, because vegetable-based production is more efficient in its use of phosphorus then livestock production.

“A radical rethink of how we farm so that adequate phosphorus levels can be maintained without reliance on mined phosphate, is crucial for ensuring our future food supplies.” says Isobel Tomlinson, Soil Association policy officer and author of the report.